OpenGL is a graphics standard and API which targets the desktop and workstation markets. It is designed to be easy to accelerate with dedicated computer hardware, and hence most implementations give greatly improved performance over traditional software rendering. Currently, OpenGL is used for ...

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714 views

Is the “impossible object” possible in computer graphics?

This may be a silly question but I want to know the answer to it. I saw this thing called the "impossible object", while they're many different images of this online, it's suppost to be impossible ...
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votes
5answers
793 views

What are some low-level performance tweaks for iPhone games written in c?

I'm interested in some performance tweaks for a relatively simple OpenGL ES based 2D iPhone game. What performance tweaks have you found? The performance of the game is pretty good on most devices ...
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3answers
4k views

How can I get started programming OpenGL on Mac OS X?

I'm trying to start OpenGL programming on a Mac, which brings me into unknown territory on a lot of things. During the day, I'm a Web Developer, working in C# and before that in PHP and Delphi, all ...
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3answers
3k views

Trapping mouse inside window in OpenGL with GLUT?

I perfectly understand that GLUT is limited and the following problem can't probably be solved with OpenGL/GLUT, but since I don't know exactly if it can or not, I better just ask. Maybe I'm doing ...
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2answers
555 views

3D models on 2D tilemap perspective when scrolling

I am creating a small top-down game, where the player traverses a 2D tilemap, with an illusion of depth provided by 3D models for things like buildings or trees. Having gotten to the point where I ...
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2answers
2k views

OpenGL: Is it possible to use VAO's without specifying a VBO

On all the tutorials I can find about VAO's (Vertex Array Objects), they show on how to use them by configuring vertex attributes and binding a VBO (Vertex Buffer Object). But I want to create a VAO ...
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2answers
3k views

In OpenGL Can I Discover the Depth Range of a Depth Buffer?

I am doing a GL multi-pass rendering app for iOS. The first pass renders to a depthbuffer texture. The second pass uses the values in the depth buffer to control the application of a fragment shader. ...
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2answers
712 views

Atmospheric Scattering

I want to add some nice atmospheric scattering to my 3D game engine but I am very concerned with conserving resources. I am not very familiar with how its done but can someone please give me some ...
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4answers
552 views

Creating a voxel world with 3D arrays using threads

I am making a voxel game (a bit like Minecraft) in C++(11), and I've come across an issue with creating a world efficiently. In my program, I have a World class, which holds a 3D array of Region ...
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2answers
2k views

Toggle Fullscreen at Runtime

Using the library GLFW, I can create a fullscreen window using this line of code. glfwOpenWindow(Width, Height, 8, 8, 8, 8, 24, 0, GLFW_FULLSCREEN); The line for creating a standard window looks ...
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2answers
710 views

Disadvantages of using multiple versions of OpenGL in LWJGL?

So, I'm trying to figure out LWJGL, and my goal is to use OpenGL 3.2 (because pretty shaders are pretty). But in every tutorial I can find for LWJGL, they import a bunch of different OpenGL versions ...
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votes
1answer
351 views

Why would I support multiple rendering engines simultaneously?

I've seen some games from the early 2000s that had a launcher where you could select the rendering engine you wanted to use: DirectX or OpenGL. Maybe I haven't looked hard enough, but I haven't seen ...
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2answers
1k views

Integrate LibRocket With SDL And OpenGL

I been currently involved in a game project and we reach the point we're want to added the GUI for menus and other stuff but the time that we maybe spent developing our own system could cost us a bit ...
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votes
2answers
530 views

Which are the most futureproof languages for graphics (shader) programming?

I have written some GLSL and Cg shaders a couple years back. I am starting another graphics engine project and I want to choose my technologies carefully so that my code will be accessible years down ...
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votes
3answers
4k views

Open Source Engine for RTS [closed]

I must write a cross-platform real-time-strategy game within 2-3 months. I want use C++ and OpenGL and am looking for an engine. The engine must be open source and work under both Linux and Windows. ...
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1answer
408 views

Is a 10 meg 2048x2048 bitmap too big a size texture to use in an OpenGL game?

This is a speed question, I have a texture, which is 2048 per 2048, the texture is designed to run in big resolutions (1920x1080 for example). The problem is, that the texture have a size of 10MB in ...
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1answer
4k views

OpenGL: Resizing Display and glOrtho/glViewport

I have researched this question from several sources and have yet to find a firm answer saying that "yes that is correct thinking" or "no, here is how it's done." I am trying to ensure resolution ...
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votes
2answers
198 views

Game has noticeable frame drops but when through a profiler it always runs smooth

I'm trying to optimize my PC game but I can find the bottleneck since every time I run it through a profiler (gDEBugger) it runs smooths. When running outside gDEBugger I get these annoying hiccups. ...
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3answers
11k views

glTranslate, how exactly does it work?

I have some trouble understanding how does glTranslate work. At first I thought it would just simply add values to axis to do the transformation. However then I have created two objects that would ...
5
votes
2answers
717 views

Best way to do buttons for an OpenGL ES iPhone game

I'm making a simple 2d game in OpenGL ES and I want to add movement buttons to it. What's the best way of going about this? In previous projects I've simply added UIButtons to the view but I hear ...
5
votes
2answers
940 views

What is causing these texture edge artifacts on some video cards?

I have a 2d heightfield converted into a very simple mesh and textured with tiles from a texture atlas. The tiles texture is drawn with: glTexParameterf(GL_TEXTURE_2D,GL_TEXTURE_WRAP_S,GL_CLAMP); ...
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2answers
1k views

Generating geometry when using VBO

Currently I am working on a project in which I generate geometry based on the players movement. A glorified very long trail, composed of quads. I am doing this by storing a STD::Vector, and removing ...
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2answers
1k views

3D primitive rendering library

I am looking for a library which would easily allow me to render shapes (cubes, spheres, lines, circles, etc.) in 3D3 and OpenGL if possible. I want to be able to rapidly design visual debugging tools ...
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1answer
1k views

How to use modern OpenGL for 2D games?

I've found a plethora of "modern" OpenGL (3.0+) tutorials for 3D, but I have found next to nothing when looking for information on how to use it for 2D game development. How can I get started using ...
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2answers
231 views

Include deprecated OpenGl “immediate mode” context in OpenGl 4?

I'm working on an app that uses immediate mode in all of it's draw routines and I'd like to keep those functions intact when updating our graphics drivers to OpenGl 4. My intention is to get the app ...
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3answers
4k views

Importing and Displaying .fbx files

I have a little problem with importing/displaying .fbx files. I checked the examples but the ones which I am intrested the most (animation and texture) are badly documented for understanding by ...
5
votes
1answer
343 views

Cheap ways to do scaling ops in shader?

I've got an extensive world terrain that uses vec3 for the vertex position attribute. That's good, because the terrain has endless gradations due to the use of floating point. But I'm thinking about ...
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votes
2answers
1k views

Should the modelview and projection matrices be calculated in the shader or on the CPU?

At minimum I would have a camera with rotation and world position; projections parameters such as angle of view and perspective vs. orthographic; and meshes with scale, angle, and world position. ...
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votes
2answers
652 views

How can I make the switch from immediate mode to VBOs?

I've been using OpenGL for a short time now- and I'd like some clarification on VBOs. As I understand it, a VBO is an object stored on VRAM. In immediate mode, to apply a texture we simply bind it and ...
5
votes
2answers
373 views

Should I batch up debug primitives for rendering in modern OpenGL?

I've recently started porting some old rendering demos I did to modern OpenGL. I had a debug drawing class in my old code which used immediate mode glBegin(), glEnd() etc. for rendering debug objects ...
5
votes
1answer
515 views

How to insert and remove blocks quickly in a Minecraftian world?

I currently have volume data for the world stored as an array of booleans. I then check each empty block and if it has non-empty neighbors the faces get drawn. This prevents me from sending a bunch ...
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votes
4answers
3k views

Can't understand these UV texture coordinates (range is NOT 0.0 to 1.0)

Hey, hello guys, I am trying to draw a simple 3D object generated by Google SketchUp 8 Pro onto my WebGL app, the model is a simple cylinder. I opened the exported file and copied the vertices ...
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votes
3answers
3k views

how to add water effect to an image

This is what I am trying to achieve: A given image would occupy say 3/4th height of the screen. The remaining 1/4th area would be a reflection of it with some waves (water effect) on it. I'm not sure ...
5
votes
1answer
124 views

Spherical harmonics lighting interpolation

I want to use hardware filtering to smooth out colors in texels of a texture when I'm accessing texels at coordinates that are not directly at the center of the texel, the catch being that the texels ...
5
votes
1answer
368 views

What are the rest of the blending functions used for?

In general, I know of five ways to make use of blending functions (these are for OpenGL, but replace glBlendFunc() with SetRenderState(D3DRS_SRCBLEND) and SetRenderState(D3DRS_DESTBLEND) for DirectX): ...
5
votes
1answer
714 views

What is actually drawn when glDrawArrays and glDrawElements are called?

In my journey out of immediate mode I've come across a snag that I haven't been able to find a decent answer for in any tutorial or API, namely: Which data structures are actually invoked when I make ...
5
votes
1answer
6k views

How does gluLookAt work?

From my understanding, gluLookAt( eye_x, eye_y, eye_z, center_x, center_y, center_z, up_x, up_y, up_z ); is equivalent to: glRotatef(B, 0.0, 0.0, 1.0); ...
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votes
2answers
628 views

Geometry shader for multiple primitives

How can I create a geometry shader that can handle multiple primitives? For example when creating a geometry shader for triangles, I define a layout like so: layout(triangles) in; ...
5
votes
1answer
781 views

VBO and gl*Pointer management practises?

I'm aware it's not a simple yes/no question and for the moment I can't tell if it can be simply answered, or is it topic for a long discussion which is not suitable for our Q&A format. I want to ...
5
votes
1answer
611 views

Difference between the terms Material & Effect

I'm making an effect system right now (I think, because it may be a material system... or both!). The effects system follows the common (e.g. COLLADA, DirectX) effect framework abstraction of Effects ...
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votes
1answer
1k views

Problem with Assimp 3D model loader

In my game I have model loading functions for Assimp model loading library. I can load the model and render it, but the model displays incorrectly. The models load in as if they were using a seperate ...
5
votes
2answers
342 views

How does this snippet of code create a ray direction vector?

In the Minecraft source code, this code is used to create a direction vector for a ray from pitch and yaw:' float f1 = MathHelper.cos(-rotationYaw * 0.01745329F - 3.141593F); float f3 = ...
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votes
1answer
990 views

How does one get adjacency information in a geometry shader?

If you use triangle_adjacency as the input type of a geometry shader, do you need to do something on the client side besides make the primitive mode triangle_adjacency? Basically what I'm asking do ...
5
votes
2answers
7k views

Does Unity for PC use Direct3D or OpenGL?

I am a mac developer using Unity and I hardly use a PC. When you build a Unity game for Windows, does it use Direct3D or OpenGL? P.S. I'm not sure if it's called Direct3D or DirectX
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votes
4answers
9k views

Wavefront *.obj loader in C++

I'm creating a game using OpenGL (via SDL) and C++ (via Visual Studios 2010 Professional). During the game, I will be using 3D character animation. I'd like to use wavefront *.obj files for all the 3D ...
5
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1answer
716 views

GLSL shader without a vertex array

Ok so I have a idea for a neat GPU driven curve renderer, and I realised that the vertex shader can be hardwired to generate points of the curve segment (to be rendered as a line strip) without ...
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votes
1answer
202 views

With what projection matrix should I render a portal to a texture?

I'm using OpenGL. I have problem with my engine's portal implementation. To create the first portal I do: create a virtual camera with the position of the second portal and the correct orientation ...
5
votes
1answer
329 views

OpenGL ES 2.0 obscured texture is visible

Hi, I am using LibGDX and OpenGL 2.0 to create a game. So far I have created two meshes. The front mesh is the one with the brown circle texture and another mesh on the top with a green to white ...
5
votes
1answer
252 views

Sprite with alpha Blending in 3D world

I'm working on a game in a 3D world with elements 2D only (Like Don't starve game) for Android and IOS. Currently, I've managed "Sprite" without alpha blending, I've just put a condition in the pixel ...
5
votes
1answer
1k views

How to do simple bump mapping

I'm trying to do bump mapping, and I'm getting fairly close at achieving my goal. I miss one crucial piece of my puzzle to have bump mapped effect in my scene; I need to transform the normals from my ...